Motor is a 93, switch on the motor works. 12V at the connector (this is in an 84 K30 and there was no resistor) but when you plug the wiring into the KSB voltage drops to ~.4V.

Any idea why? Is the KSB bad? All of the wiring is stock sized or bigger.



I'm chasing a rough start/white smoke/surging problem which really sounds like the KSB, especially since it apparently doesn't work, but there's more there it seems. The rough start/white smoke/surging was very consistent and stopped as the motor warmed up. Suddenly, however, the motor started surging all the time. I had to turn the idle up significantly so it would idle at all. The truck drives great otherwise. Several days on the road, a fuel filter and some cleaner later, the surging went away (didn't happen right away with the filter, I think something in the pump is sticking on account of some really old bio diesel that had been sitting in the system).

Now occasionally when you start the truck, especially if it's cooler, the throttle won't control anything. Moving the throttle lever on the pump does not change how the truck runs at all. Once it warms up for a minute or so everything is back to normal. Any ideas on all of this?

 

Any ideas?

The truck also revs REALLY high when you first start it, completely on it's own.

 

2 possibilities;
1.) the KSB coil is shorted.
2.) the supply wire has a high resistance.

 

I dont even have my ksb hooked up since the intake temp switch dont work. It runs the same as always.

 

Makes a huge difference in cold climates. I lost the connection on my 92 and it was hard to keep running until the engine warmed up. It also put out a lot of white smoke until then.

 

No KSB here either. (I have one, but it is not hooked up) I have my grid heater relays hooked up to a momentary toggle switch. I energise the grids for about 15 seconds on a cold start, and will cycle the grids a few seconds at a time for about 30 seconds after I first start it. The warm air stops all surging and most of the smoke.

Edit....
My engine is a '89 non intercooled. If I understand correctly, with no power to the KSB, it is in the state it would be in cold, and stays that way. I think on a '93 intercooled engine, you have to have power to your KSB to get to the state where mine is de-energised. Do a search for KSB and you will find more information. I don't know exactly what the KSB does, something with timing?? If not that, I think it controls the intermodal reactance with the disgronifier's sperving shaft when the quadjufodulator dingle arm is in contact with the dumisary bearing.

In the 30,000 miles I have driven my truck, there has been no problems due to no KSB

 

I am in the mountains in Colorado but it's still nice here, the problem occurs even in 80 degree weather. The grid heater isn't hooked up yet, though I don't think that is causing this either (it's a repower into an older Chevy).

It's tough to blame something inside the pump when the problem "comes and goes" to some degree: the truck surged only at start up and required the idle to be set much higher, then the truck surged at start up AND when warm for a couple weeks, now it's back to surging only at idle.

I've only put ~1000 miles on the motor since it was swapped in, it was a good running motor that sat for a couple years between being pulled and re-installed. The most confusing part is that it ran the best right after being swapped in, it really ran perfect and fired/idled perfect on the first rotation of the starter.

The motor was run on biodiesel and it's likely that's what was sitting in the injection pump etc, when I installed my fuel pin I did notice some varnish/gummy type stuff on the parts. I cleaned everything up with thinner and the truck has run on fresh diesel with some cleaner thrown in most of the time.

What's the fix for the KSB coil being shorted? I'm an ME by trade and spent my time in college building/fixing cars to get by, I needed a diesel tow rig for my rock crawling buggy and built this truck so I'm not new by any means. I am, however, extremely new to diesel motors so any help is appreciated

 

Just curoius, it the KSB coil the piece that is bolted to the head with the sheild over it? Or are you talking about the part that turns it on/off?

 

The KSB is the cylinder looking thing on the side of the injection pump with a wire and a small tube coming off of it.
If the coil is shorted, it will have to be replaced.
Here is how to test the KSB.
Get yourself a jumper wire that will reach the battery. Disconnect the wire from the KSB and hook up the jumper direct to the battery. If you get a lot of sparks the coil is shorted. Run the engine until it is warmed up. Listen closely to the engine while it idles and disconnect the jumper from the battery. You should hear a slight change in the sound of the engine as you connect and disconnect the jumper. That means the KSB is working.

 

If you have a wire jumped to the ksb, if you give it a little throttle it will really make the engine loud if its working. Dont leave the wire on there though unless you have a switch to shut it off before you drive the truck.

 

Tried the jumper, it sparks but not fireworks or anything. KSB is definitely not working.

If the coil is shorted, can it be replaced or does the whole KSB need to be replaced?

 

Anyone know if the coil is separate? My FSM says that nothing on the pump is serviceable, of course.

 

Yes, it unscrews off the end of the KSB.

 

Any idea on a part number or a place to get one?

My local Cummins dealer can't get anything but a complete pump.

 

A Bosch dealer or a parts pump.